Zinc based metal–organic framework for nickel adsorption in water and wastewater samples by ultrasound assisteddispersive-micro solid phase extraction coupled to electrothermal atomic absorption spectrometry

In this research, Zn۲(BDC)۲(DABCO) metal–organic framework (MOF) as a solid phase was used for separation and preconcentration toxic nickel ions (Ni) from water samples by ultrasound assisteddispersive- micro solid phase extraction coupled to electrothermal atomic absorption spectrometry (USA-D-μ-SPE/ET-AAS). The MOF nanostructure was characterized by field emissionscanning electron microscope (FE-SEM) and transmission electron microscopey (TEM) for presentation of morphology and size of MOF synthesis. By procedure, ۲۵ mg of Zn۲(BDC)۲(DABCO) as MOF adsorbent was added to ۲۵ mL of water samples and then, Ni ions chemically adsorbed based on dative bonding of nitrogen in DABCO (۱,۴-diazabicyclo [۲.۲. ۲]octane); N۲(C۲H۴)۳) at pH=۸. The adsorbent was separated from liquid phase by syringe cellulose acetate filters (SCAF, ۰.۲ μm) and Ni ions back extracted from MOF adsorbent before determined by ET-AAS. The maximum recovery of MOF for nickel ions as a physically and chemically adsorption was obtained ۳۴.۶% and ۹۸.۸% at pH=۳ and ۸, respectively. The capacity adsorption of Zn۲(BDC)۲(DABCO), MOF for nickel was acquired ۱۲۵.۷ mg g-۱ at pH=۸. By procedure, the preconcentration factor (PF), LOD, and linear range were achieved ۴۸.۷, ۰.۰۳ μg L−۱ and ۰.۱۰-۲.۸۸ μg L−۱, respectively (RSD<۱.۲۶). The validation of proposed method was successfully obtained by ICP- MS analysis in real samples.

Keywords:

Metal–organic framework , Nickel , Adsorption , Dispersive- micro solid phase extraction , Water sample , Electrothermal atomic absorption spectrometry